Position sensors are frequently employed in automotive vehicles to sense and monitor the position of an object that may travel through various positions. For example, position sensors are commonly employed to monitor the position of an electrically powered door so as to determine whether the door is in the open position or closed position. Absolute position sensors provide a sensed position signal which contains information about the absolute position relative to a predetermined position. Thus, in a power door application, the use of an absolute position sensor allows for the determination of the absolute position of the power door relative to the open and closed positions.
Automotive vehicles increasingly are equipped with electrically powered devices such as side entry doors and rear entry doors (or lift gates), each of which are powered by an electric motor that receives electric current from the vehicle battery. Each of these power doors also typically employs an absolute position sensor in order to determine the absolute position of the door. In addition, the power doors are often controlled via a remote control switch which allows the operator of the vehicle to remotely control the opening and closing of the door. In conventional vehicles, the absolute position sensor is generally configured to be continuously powered whenever the power door is in an open position so that the sensor continuously monitors the position of the open door until the door is closed. The absolute position sensor has an electrically powered sensing device that is also supplied with electric power from the vehicle battery. If the power door is left in the open position, the position sensor continues to drain current from the vehicle battery as long as the sensor remains on. The continued usage of the sensor during an extended time period drains current from the vehicle battery and, thus could result in substantial discharge of the battery. This can lead to a drained battery after an extended period of time.
Accordingly, it is therefore desirable to provide for an absolute position sensor that has reduced power consumption requirements. It is further desirable to provide for such an absolute position sensor that operates at low power so as to reduce current drain from the limited energy supply of a battery. It is particularly desirable to provide such an absolute sensor that exhibits reduced power consumption for use on vehicles that have a limited battery supply.